Aluminum clad cookware per se is known. U.S. Pat. No. 2,171,040 teaches producing strips of stainless steel clad with aluminum which are then cut and deep drawn to form the cooking utensil. Production of clad cookware in accordance with said patent requires the entire outer surface of the utensil to be defined by the aluminum layer.
U.S. Pat. No. 3,173,202 teaches a utensil wherein only the bottom surface of the utensil is clad with a layer of aluminum. U.S. Pat. No. 3,173,202 teaches the application of an aluminum spray to the bottom surface of the stainless steel utensil and thereafter bonding an aluminum disk to the aluminum spray.
The apparatus for applying aluminum spray is costly and noisy. In view of the noise associated with such apparatus, government regulations require that the spray station be soundproofed for the protection of workers. The use of an aluminum spray requires an extra finnishing step to remove overspray. The present invention is directed to the problem of producing a stainless steel utensil having an aluminum disk bonded only to the bottom surface of the utensil but without using an aluminum spray as taught by the last-mentioned patent. It has been found that the aluminum spray step can be eliminated and at the same time produce a stronger utensil having a more uniform bond which in turn provides better heat transfer for quicker heating of foods. Also, it was found that the utensil can be manufactured less expensively while increasing production. In order to eliminate the aluminum spray, it was found that it was necessary to change the heating method for heating the disk and utensil, change the heating temperature only for the utensil, increase the pressure for bonding the disk to the utensil, and that the utensil and disk are preferably heated separately.